Routes of abuse of prescription opioid analgesics: a review and assessment of the potential impact of abuse-deterrent formulations

Prescription opioid analgesics are an important treatment option for patients with chronic pain; however, misuse, abuse and diversion of these medications are a major global public health concern. Prescription opioid analgesics can be abused via intended and non-intended routes of administration, both intact or after manipulation of the original formulation to alter the drug-delivery characteristics. Available data indicate that ingestion (with or without manipulation of the prescribed formulation) is the most prevalent route of abuse, followed by inhalation (snorting, smoking and vaping) and injection. However, reported routes of abuse vary considerably between different formulations. A number of factors have been identified that appear to be associated with non-oral routes of abuse, including a longer duration of abuse, younger age, male sex and a rural or socially deprived location. The development of abuse-deterrent formulations of prescription opioid analgesics is an important step toward reducing abuse of these medications. Available abuse-deterrent formulations aim to hinder extraction of the active ingredient, prevent administration through alternative routes and/or make abuse of the manipulated product less attractive, less rewarding or even aversive. There are currently five opioid analgesics with a Food and Drug Administration abuse-deterrent label, and a number of other products are under review. A growing body of evidence suggests that introduction of abuse-deterrent opioid analgesics in the USA has been associated with decreased rates of abuse of these formulations. The availability of abuse-deterrent formulations therefore appears to represent an important step toward curbing the epidemic of abuse of prescription opioid analgesics, while ensuring the availability of effective pain medications for patients with legitimate medical need.